Zero-phonon line (ZPL) emissions have key applications in single-photon emission sources, quantum information processing, and single-molecule spectroscopy. All recent attempts to realize ZPL emissions are based on the techniques of confining and doping molecules in matrixes or solutions in low-temperature Shpol'skii systems. The requirement of two-component systems reduces the light emission efficiency from the molecules and limits their applications in solid-state electronic applications and quantum computing devices. Here, we report the first experimental demonstration of the Shpol'skii effect in a one-component organic solid-state system at low temperature. We observe a ZPL emission with a width of ∼1 to 2 nm and a high value of the Debye-Waller factor (0.72) from our epitaxially grown highly crystalline and ordered 1D organic nanowire, which is attributed to a specific molecular configuration and a higher degree of molecular orientation as compared to that of the bulk thin film counterpart. Our results pave the way for organic 1D wires (with quasi-line spectra) for applications in lasing, nanosensors, and interconnects/functional units in next-generation miniaturized optoelectronics.
Keywords: Shpol’skii effect; crystallinity; organic nanowires; quasi-line spectra.